I have heard of alot of guys cleaning the throttle body. What is this process? Anyone have directions? What cleaning chemical?

 

This is how I did my '89, I think yours should be pretty much the same but I'm not positive. I'm sure someone else will chime in to confirm.

Throttle Body maintenance 101:
(YOU WILL NEED A DIGITAL MULTIMETER IF YOU TAKE THE TPS OFF! DON’T ATTEMPT TO REMOVE THE TPS IF YOU DON’T HAVE ONE, IT IS MANDATORY!)

You should also buy the gasket kit from GM that includes the 4 gaskets and costs about $25.

Using your screwdriver remove the air duct in front of the throttle body, now open the throttle by hand (engine off of course) and feel behind the throttle blades. Did your fingers go all black and gungy (yucky isn't it). You need to get that throttle body off and scrub it cleaner than clean can be.

Preparation: Go and buy some throttle body cleaner (NOT CARBURETOR CLEANER), and buy yourself a new toothbrush, your old one just got a new life.

Get an old bowl or something similar, rags and perhaps some of those lovely rubber surgical gloves. Getting right on in there remove the 3 pin connector from the throttle position sensor, and remove all the pipe work going to the throttle body, there is a little water spillage, not much. Also remove the IAC connector (a 4 wire square connector) it's a bit fiddly to get to. Now the tricky part, the throttle cables need to be released, (manual and auto cars are different), the cables are fixed with wonderful things called Jesus clips, you slide a screwdriver under it and ping it disappears, you mutter 'Jesus where did that go' - what a name for an item. Best to cover the area with a cloth to capture any pinging that goes on.

With the cables released the throttle body should be free to remove. Undo the four long bolts holding it to the plenum, careful when prizing it apart, do not damage the gasket. Now you thought you were clear didn't you, nope, GM put a little booby trap underneath. There is a small vacuum tube with a rubber elbow that needs to be pulled off. You're free!

Now comes the really dirty part. Put the throttle body in the bowl and spray with throttle body cleaner and scrub like crazy, especially around the throttle blades. Its great, really messy but the final spray just cleans it all off and there you have a gleaming throttle body.

Now using a 31 or 32mm spanner remove the IAC valve (that's the large black looking thing on the side), mind the gasket. Clean the spring and pintle and if you can get inside the orifice and clean the seat area. Make sure that the small hole going from the throttle mouth to the IAC is clear. Finally just spray the spring and pintle with WD40 and replace the IAC valve.

Final check - and perhaps another blast with the cleaner to remove any surface muck still there. You may want to soak a rag with throttle body cleaner and clean as far in the plenum as you can get. Allow to dry and replace the throttle body on the plenum, taker great care with the gasket ensure it is positioned correctly. Ensure all the connectors cables and pipes are back on (don't forget the little tube underneath).

This may be a good point to check and adjust your throttle position sensor. Get two paper clips, straighten out and slide into the end of the TPS sensor connector, A (earth) and B (tps output), keep the wires separate and turn the ignition on, measure the voltage at the wires and adjust by loosening the torx bolts, if necessary, to 0.54 volts - this is the normal idle setting.

Self satisfaction. Job done now you should start your Corvette and stand back to admire the even tickover and you will marvel at the smooth response the car now seems to have. If nothing else you have pampered and tinkered for about an hour, got filthy, therefore justifying your time and got a tangible result afterwards, all that remains to do is test drive the car to the nearest (or in fact not so nearest pub). Congratulate yourself with a beer and apply wide beaming grin.
:cheers: :) :seeya

 

I just removed it and cleaned it with carb clearner and a tooth brush and replaced all caskets. It only took about a hour.

 

I'll tell yall somethin........I teach this stuff for a living..... and we need some textbooks that are as enjoyable to read as what vettboy 89 just wrote here........ I can't add a thing to what he said and I enjoyed reading it :cheers: :cheers: :cheers: :seeya

 

Thanks Vettmech :cheers:

 

my pleasure :cheers:

 

I have aggressivley cleaned the TB mounted in the car with FI cleaner, and the throttle got a bit sticky. It would hang up and not idle down right. How do you avoid this?

 

What is this vacuum tube? I noticed that mine has been broken and repaired before right as the elbow angles. There's no vacuum leak right now, but I'm wondering how important it is so that I can possibly reevaluate how soon I need to replace it.

 

I think that one goes to your purge canistor, but I can't remember off the top of my head, my cars not here right now. :(

 

Do you have to remove the IAC to clean the throttle-body? I'd rather not mess with it if I don't have to.

 

It just screws in. I would remove it so you can clean out the passage better and to keep the cleaner from running up inside the IAC.

 

Don't you have to reset the idle or something if you remove it though?

 

Sure don't. I believe that's only if you remove the TPS.


[Modified by Tourney3p0, 4:26 PM 10/11/2002]